code: def test_how(how):
      left = cudf.DataFrame(
          {"x": [1, 2, 3, 4, None], "y": [1.0, 2.0, 3.0, 4.0, 0.0]}
      )
      right = cudf.DataFrame(
          {"x": [2, 3, None, 2], "y": [20, 30, 0, 20]}
      )
  
      dleft = dd.from_pandas(left, npartitions=2)
      dright = dd.from_pandas(right, npartitions=3)
  
      expected = left.merge(right, how=how, on="x")
      result = dleft.merge(dright, how=how, on="x")
  
      dd.assert_eq(
          result.compute().to_pandas().sort_values("x"),
          expected.to_pandas().sort_values("x"),
          check_index=False,
      )
  
file_path: cudf/python/dask_cudf/dask_cudf/tests/test_join.py
imports: from functools import partial
  import numpy
  import pandas
  import pytest
  from dask import dataframe
  import cudf
  import dask_cudf
label_desc: Use image node_id 7 for calling a global function with example usage: test_how(how) without return types